NEW YORK (Reuters Health)—Pneumococcal vaccination yields a satisfactory antibody response in patients with systemic sclerosis (SSc), but synthetic disease-modifying antirheumatic drugs (DMARDs) might reduce the vaccine response in these individuals, according to a report from Sweden.

The prospective study, published online Jan. 8 in Rheumatology, evaluated the response to either pneumococcal conjugate vaccine (PCV13) or pneumococcal polysaccharide vaccine (PPV23) in three groups: 32 SSc patients not receiving a DMARD, 12 SSc patients receving a synthetic DMARD, and 49 healthy controls. All participants had been either vaccine-naive or had not received a pneumococcal vaccine in at least five years.1

For both vaccines, the antibody response to two capsular polysaccharide serotypes (6B and 23F), as well as functionality of antibodies for 23F, was as good in the SSc patients not receiving DMARDs as in the controls. The DMARD-treated SSc group, however, had significantly fewer antibody responders, although antibody functionality was preserved.

Both vaccines were found to be safe and associated with only mild side effects.

“These results suggest that immunomodulating drugs, but not SSc itself and/or immunological disturbance as a part of this disease, affect the ability to produce a sufficient amount of vaccine-specific antibodies, but not their function,” the researchers write.

“Pneumococcal vaccination is safe and immunogenic in patients with SSc, although treatment with DMARDs may decrease the vaccine-specific antibody response,” they conclude. They further suggest that the currently recommended prime-boost vaccination strategy of using a dose of PCV13, followed by a dose of PPV23, could enhance the vaccines’ immunogenicity in immunosuppressed patients.

The authors believe that theirs is the first report on the immunogenicity and tolerability of two currently licensed pneumococcal vaccines (polysaccharide and conjugate) in adults with SSc vs. controls.

The findings are consistent with the researchers’ previous work showing an impaired antibody response after pneumococcal vaccination in patients with rheumatoid arthritis treated with methotrexate, corresponding author Dr. Meliha C. Kapetanovic, of Lund University, Sweden, told Reuters Health by email.

“The same pattern was seen irrespective of disease activity, type of disease (diffuse or limited) or whether patients were vaccinated with a polysaccharide or a more immunogenic conjugate vaccine,” she adds. “These results could probably be extrapolated to all patients with inflammatory rheumatic diseases taking traditional synthetic DMARDs.”

“Since there is a risk of insufficient response and thus inadequate protection against infections in patients on DMARDs,” Dr. Kapetanovic advises, “our results suggest that pneumococcal vaccine should preferably be administered before the start of such treatments.”

However, Dr. John Varga, of the Northwestern University Feinberg School of Medicine, Chicago, tells Reuters Health in a phone interview, “I would be extremely cautious” about extrapolating these findings to other rheumatic diseases, noting SSc has features, such as fibrosis, that set it aside from other rheumatic diseases.

The study was well done, with clean results, Dr. Varga adds, but it was based on a small cohort (from southern Sweden) that’s unlikely to have had much ethnic diversity.